Does Dorsal Pedal Pulse Palpation Predict Hand-Held Doppler Measurement of Ankle-Brachial Index in Leg Ulcer Patients?

Author(s): 
Mats Bjellerup, MD

Disclosure: This study has been made possible by generous grants from the Gorthon Foundation, Helsingborg, Sweden.

Introduction

Leg ulceration is a common disease that inflicts substantial suffering on the patient and causes great economic strain on the healthcare system. Several recent studies in Sweden have found a point prevalence in the healthcare system varying between 0.12 and 0.3 percent.[1,2] Leg ulceration is not a disease per se but a symptom of an underlying disease in large or small blood vessels, physical agents, such as trauma, hydrostatic or mechanical pressure, and neoplasms. In previous years, establishment of etiological diagnosis has been of poor quality. Thus, estimation of the arterial circulation has mainly rested on palpation of pedal pulses, especially in the dorsal pedal artery. Identification of the pedal pulse, however, may be difficult in many patients, especially in those with edema. In recent years, a simple diagnostic tool, the hand-held Doppler, has become available outside vascular surgery departments making etiological diagnosis on the arterial side simple and mandatory. The present report deals with the correlation between dorsal pedal pulse palpation and hand-held Doppler measurement of ankle pressure in a patient population examined at a specialized leg ulcer clinic by certified specialists in dermatology.

Methods

Patients. At the Department of Dermatology in Malmö (235,000 inhabitants), Sweden, a specialized leg and foot ulcer clinic was instituted in 1989 that aims for etiological diagnosis in every patient, standardized treatment, a limited number of local treatments, and thorough follow up of patients. Since 1993, every new patient was registered consecutively using a standardized, computerized protocol. The first 665 ulcer patients are reported.

Methods. All patients attending the leg ulcer clinic were investigated in a standardized way following a computerized protocol including relevant patient history regarding general health, previous vascular and ulcer disease, previous vascular surgery, duration of present ulcer, pain, and present treatment. A clinical investigation of both the arterial and venous circulation was carried out using a hand-held ultrasound Doppler.

On the arterial side, the investigation was carried out as pulse palpation followed by Doppler investigation. Pulse palpation was restricted to attempting to identify the dorsal pedal artery. Thus the posterior tibial artery was not searched for. Doppler investigation was started by applying a tourniquet with a manometer on the upper arm. The Doppler probe was placed over the antecubital fossa identifying the arterial pulse; the tourniquet was inflated until pulse disappearance and slowly deflated until reappearance of pulse noting the corresponding pressure (brachial pressure). The tourniquet was then placed just above the ankle. The Doppler probe was placed over the dorsal pedal artery identifying the pulse; the tourniquet was inflated until pulse disappearance and slowly deflated until reappearance of pulse noting the corresponding pressure (ankle pressure). In the case of finding a pressure below the brachial pressure, the procedure was repeated with the probe over the posterior tibial artery. If this pressure was found to be above the dorsal pedal artery pressure, the former was used for further calculations. Thus the “best” pressure was used. The ankle-brachial index (ABI) was calculated by dividing ankle pressure with brachial pressure approximating the value to two decimals.

Statistics. For data with one continuous variable, an unpaired t-test has been used.

Results

Patients with complete data. At closure of the data base, data regarding palpable dorsal pedal pulse was available for 583 patients. Among 183 patients without palpable pulses, ankle pressure was not performed in four (2.2%), performed without finding any arterial sound in four (2.2%), and recording incompressible arteries in two (1.1%). Among 400 patients with palpable pulses, ankle pressure was not performed in 56 (14%), performed without finding any arterial sound in four (1%), and brachial pressure was not performed in three (0.8%). Thus complete data was available for 173 patients without and 337 patients with palpable dorsal pedal pulses.

Ulcer etiology. Information on ulcer etiology was available for 490 patients. Venous etiology dominated with 55.1 percent followed by hydrostatic (defined as a traumatic ulcer in a leg without venous or arterial insufficiency and estimating 17.8%), combined veno-arterial (5.3%), decubital (4.9%), hypertensive (3.5%), arterial (3.3%), other (2.7%), rheumatic (1.6%), primary white atrophy (1.2%), neuropathic in diabetes (1.2%), pyoderma gangrenosum (1.0%), basal cell carcinoma (1.0%), arterial in diabetes (0.6%), allergic vasculitis (0.4%), squamous cell carcinoma (0.2%), and lymphedema (0.2%).

ABI vs. palpable or nonpalpable pulses. All ABI values for the two groups with palpable and nonpalpable pulses are shown in Figure 1. Mean ABI in patients with palpable pulses was 1.07 (median 1.07, range 0.35–1.79). Mean ABI in patients without palpable pulses was 0.79 (median 0.80, range 0.22–1.31). The difference was significant (p

ABI in patients with palpable pulses. The distribution of ABI within the group of patients with palpable pulses is shown in Figure 2. Fifty-two (15.4%) patients had an ABI less than or equal to 0.9 despite palpable dorsal pedal pulses.

ABI in patients with nonpalpable pulses. The distribution of ABI within the group of patients without palpable pulses is shown (Figure 2). Sixty-nine (39.8%) patients had an ABI > 0.9 despite nonpalpable dorsal pedal pulses.

Discussion

Leg ulceration is a common symptom in the elderly population. A wide range of etiologies underlying the actual ulcers is seen at a specialized leg ulcer clinic, varying from vascular disease to malignant tumor. Therefore, it is of utmost importance that the correct etiological reason is determined as soon as possible. A probable diagnosis can be established with a certain amount of accuracy relying on patient history, ulcer location, and ulcer appearance only. However, diagnosis should always be verified using a confirmative objective method.

In previous years, arterial circulation has been judged by palpation of the pedal pulse, most frequently in the dorsal pedal artery. The hand-held ultrasound Doppler has mostly been used by vascular surgeons. The present investigation was aimed at comparing palpation of dorsal pedal pulses and ankle pressure measurement with a hand-held ultrasound Doppler in the setting of a specialized leg ulcer clinic at a department of dermatology.

When estimating the arterial circulation, the concept of ABI is frequently used. ABI is an estimate of the proportion of brachial pressure measured at the ankle. Thus, it is a relative value not taking the absolute pressure value into consideration and is an estimate of leg arteriosclerosis. The normal value for ABI is frequently given as 0.9 to 1.4. When defining patients with peripheral arterial disease, different cut-off points have been used. Thus, in two recent reports concerning nonulcer patients studying different aspects of peripheral arterial disease, an ABI of

What is more interesting is to study the distribution of ABI within the two groups. In the group without palpable pulses it is noteworthy that 39.8 percent had an ABI of > 0.9. In the group with palpable pulses, it is noteworthy that 15.4 percent had an ABI of less than or equal to 0.9. Thus, the presence or absence of palpable dorsal pedal pulse is not a reliable predictor of ABI. The most serious drawback of relying on pulse palpation only is that a substantial proportion of patients with significant arterial impairment are judged as having normal pulses. Consequently, they might not be offered further proper investigation and therapy on the arterial side. Mistakes may also take place in choosing adequate compression therapy, since patients with low ABI should be recommended low-stretch bandages to avoid sub-bandage pressure during bed rest. Another drawback is the great proportion of patients with nonpalpable pulses having normal ABI. Relying on palpation only in these patients results in unnecessary laboratory investigations of peripheral circulation with subsequent costs. The use of hand-held Doppler for investigation of both the arterial and venous circulation is also a prerequisite in the cooperation between dermatologist and vascular surgeon when choosing patients suitable for vascular surgery of different kinds.[8] Choosing a lower ABI cut-off point than 0.9 obviously would decrease the proportions of patients with pedal pulse falsely predicting arterial disease.

Measurement of the arterial circulation using a hand-held Doppler is thus considered mandatory at first visit in all patients seeking advice for leg and foot ulcers.

Acknowledgments

This study could not have been completed without the skilled assistance supplied by Inger Wahldin-Håkansson, RN, who has been a responsible nurse for the leg ulcer clinic including entering data into the computerized protocol.

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